gitee:https://gitee.com/mougenan/springcloud_study.git
例如: 用户购买商品的业务逻辑。整个业务逻辑由3个微服务提供克持: 仓储服务:对始定的向品扣除色储数量, 订单服务:根狐来购需求创建订单. 帐户服务:从用户帐户中扣除全额。
单体应用被拆分成微服务应用,原来的三个模块被拆分成三个独立的应用,分别使用三个独立的数据源,业务操作需要调用三个服务来完成。此时每个服务内部的数据—致性由本地事务来保证,但是全局的数据一致性问题没法保证。
一次业务操作需要跨多个数据源或需要跨多个系统进行远程调用,就会产生分布式事务问题
Seata是一款开源的分布式事务解决方案,致力于在微服务架构下提供高性能和简单易用的分布式事务服务。 官网:Seata | Seata
一个典型的分布式事务过程: 分布式事务处理过程的ID+三组件模型: 全局唯一的事务ID:Transaction ID XID 三组件概念: Transaction Coordinator(TC):事务协调器,维护全局事务的运行状态,负责协调并驱动全局事务的提交或回滚。 Transaction Manager(TM):控制全局事务的边界,负责开启一个全局事务,并最终发起全局提交或全局回滚的决议。 Resource Manager(RM):控制分支事务,负责分支注册、状态汇报,并接收事务协调器的指令,驱动分支(本地)事务的提交和回滚。 处理过程:
TM向TC申请开启一个全局事务,全局事务创建成功并生成一个全局唯一的XID;
XID在微服务调用链路的上下文中传播;
RM向TC注册分支事务,将其纳入XID对应全局事务的管辖;
TM向TC发起针对 XID的全局提交或回滚决议;
TC调度XID下管辖的全部分支事务完成提交或回滚请求。
下载地址:Releases · apache/incubator-seata · GitHub 怎么使用:本地@Transactional、全局@GlobalTreansactional
官网:Seata | Seata
下载版本0.9.0
seata-server-0.9.0.zip解压到指定目录并修稿conf目录下的file.conf配置文件 修改:自定义事务组名称+事务日志存储模式为db+数据库连接信息
service {
#vgroup->rgroup
vgroup_mapping.my_test_tx_group = "fsp_txt_group"
#only support single node
default.grouplist = "127.0.0.1:8091"
#degrade current not support
enableDegrade = false
#disable
disable = false
#unit ms,s,m,h,d represents milliseconds, seconds, minutes, hours, days, default permanent
max.commit.retry.timeout = "-1"
max.rollback.retry.timeout = "-1"
}
mode = "db"
## file store
file {
dir = "sessionStore"
# branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
max-branch-session-size = 16384
# globe session size , if exceeded throws exceptions
max-global-session-size = 512
# file buffer size , if exceeded allocate new buffer
file-write-buffer-cache-size = 16384
# when recover batch read size
session.reload.read_size = 100
# async, sync
flush-disk-mode = async
}
## database store
db {
## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp) etc.
datasource = "dbcp"
## mysql/oracle/h2/oceanbase etc.
db-type = "mysql"
driver-class-name = "com.mysql.jdbc.Driver"
url = "jdbc:mysql://127.0.0.1:3306/seata"
user = "root"
password = "123456"
min-conn = 1
max-conn = 3
global.table = "global_table"
branch.table = "branch_table"
lock-table = "lock_table"
query-limit = 100
}
mysql5.7数据库建库seata,并在seata库中建表
修改seata-server-1.0.0\seata\conf目录下的registry.conf配置文件
type = "nacos"
nacos {
serverAddr = "localhost:8848"
namespace = ""
cluster = "default"
}
先启动Nacos端口8848
在启动seata-server
业务说明:
这里我们会创建三个服务,一个订单服务,一个库存服务,一个账户服务。 当用户下单时,会在订单服务中创建一个订单,然后通过远程调用库存服务来扣减下单商品的库存,再通过远程调用账户服务来扣减用户账户里面的余额, 最后在订单服务中修改订单状态为已完成。 该操作跨越三个数据库,有两次远程调用,很明显会有分布式事务问题。
创建数据库:
seata_order:存储订单的数据库; seata_storage:存储库存的数据库; seata_acdount:存储账户信息的数据库。
创建业务表:
seata_order库下建t_order表
CREATE TABLE t_order (
`id BIGINT(11)NOT NULL AUTO_INCREMENT PRIMARY KEY,
'user_id` BIGINT(11) DEFAULT NULL COMMENT "用户id",
`product_id` BIGINT(11)DEFAULT NULL COMMENT "产品id",
`count` INT(11) DEFAULT NULL COMMENT "数量",
`money` DECIMAL(11,0)DEFAULT NULL COMMENT "金额",
`status` INT(1) DEFAULT NULL COMMENT "订单状态:0:创建手; 1:已完结"
)ENGINE=INNODB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8;
seata storage库下建t_storage表
CREATE TABLE t_storage (
`id` BIGINT(11)NOT NULL AUTO_INCREMENT PRIMARY KEY,
`product_id` BIGINT(11) DEFAULT NULL COMMENT "产品id",
`total` INT(11) DEFAULT NULL COMMENT "总库存",
`used` INT(11) DEFAULT NULL COMMENT "已用库存",
`residue` INT(11) DEFAULT NULL COMMENT "剩余库存"
)ENGINE=INNODB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
INSERT INTO seata_storage.t_storage(`id`,`product_id`,`total`,`used`,`residue`)VALUES (1,'1',"100" , "0", "100");
seata_account库下建t_account表
CREATE TABLE t_account (
`id`BIGINT(11)NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT "id",
`user_id` BIGINT(11) DEFAULT NULL COMMENT "用户id",
`total` DECIMAL(10,0) DEFAULT NULL COMMENT "总额度",
`usedT` DECIMAL(10,0) DEFAULT NULL COMMENT "已用余额",
`residue` DECIMAL(10,0)DEFAULT '0' COMMENT "剩余可用额度"
)ENGINE=INNODB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
INSERT INTO seata_account.t_account(`id`,`user_id`,`total`,`usedT`,`residue`)
VALUES (1,1,"1000","0","1000");
3个库分别创建回滚日志表:就是分别粘贴:\seata-server-0.9.0\seata\conf目录下的db_undo_log.sql。
最终效果:
下订单->减库存->扣余额->改(订单)状态
创建seata-order-service2001项目
pom文件:
com.alibaba.cloud
spring-cloud-starter-alibaba-seata
seata-all
io.seata
io.seata
seata-all
0.9.0
application.yml
server:
port: 2001
spring:
application:
name: seata-order-service
cloud:
alibaba:
seata:
tx-service-group: fsp_tx_group
nacos:
discovery:
server-addr: localhost:8848
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/seata_order
password: 123456
username: root
feign:
sentinel:
enabled: true
logging:
level:
io:
seata: info
mybatis:
mapper-locations: classpath:mapper/*.xml
file.conf
transport {
# tcp udt unix-domain-socket
type = "TCP"
#NIO NATIVE
server = "NIO"
#enable heartbeat
heartbeat = true
#thread factory for netty
thread-factory {
boss-thread-prefix = "NettyBoss"
worker-thread-prefix = "NettyServerNIOWorker"
server-executor-thread-prefix = "NettyServerBizHandler"
share-boss-worker = false
client-selector-thread-prefix = "NettyClientSelector"
client-selector-thread-size = 1
client-worker-thread-prefix = "NettyClientWorkerThread"
# netty boss thread size,will not be used for UDT
boss-thread-size = 1
#auto default pin or 8
worker-thread-size = 8
}
shutdown {
# when destroy server, wait seconds
wait = 3
}
serialization = "seata"
compressor = "none"
}
service {
#vgroup->rgroup
vgroup_mapping.fsp_txt_group = "default"
#only support single node
default.grouplist = "127.0.0.1:8091"
#degrade current not support
enableDegrade = false
#disable
disable = false
#unit ms,s,m,h,d represents milliseconds, seconds, minutes, hours, days, default permanent
max.commit.retry.timeout = "-1"
max.rollback.retry.timeout = "-1"
}
client {
async.commit.buffer.limit = 10000
lock {
retry.internal = 10
retry.times = 30
}
report.retry.count = 5
tm.commit.retry.count = 1
tm.rollback.retry.count = 1
}
## transaction log store
store {
## store mode: file、db
#mode = "file"
mode = "db"
## file store
file {
dir = "sessionStore"
# branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
max-branch-session-size = 16384
# globe session size , if exceeded throws exceptions
max-global-session-size = 512
# file buffer size , if exceeded allocate new buffer
file-write-buffer-cache-size = 16384
# when recover batch read size
session.reload.read_size = 100
# async, sync
flush-disk-mode = async
}
## database store
db {
## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp) etc.
datasource = "dbcp"
## mysql/oracle/h2/oceanbase etc.
db-type = "mysql"
driver-class-name = "com.mysql.jdbc.Driver"
url = "jdbc:mysql://127.0.0.1:3306/seata"
user = "root"
password = "123456"
min-conn = 1
max-conn = 3
global.table = "global_table"
branch.table = "branch_table"
lock-table = "lock_table"
query-limit = 100
}
}
lock {
## the lock store mode: local、remote
mode = "remote"
local {
## store locks in user's database
}
remote {
## store locks in the seata's server
}
}
recovery {
#schedule committing retry period in milliseconds
committing-retry-period = 1000
#schedule asyn committing retry period in milliseconds
asyn-committing-retry-period = 1000
#schedule rollbacking retry period in milliseconds
rollbacking-retry-period = 1000
#schedule timeout retry period in milliseconds
timeout-retry-period = 1000
}
transaction {
undo.data.validation = true
undo.log.serialization = "jackson"
undo.log.save.days = 7
#schedule delete expired undo_log in milliseconds
undo.log.delete.period = 86400000
undo.log.table = "undo_log"
}
## metrics settings
metrics {
enabled = false
registry-type = "compact"
# multi exporters use comma divided
exporter-list = "prometheus"
exporter-prometheus-port = 9898
}
support {
## spring
spring {
# auto proxy the DataSource bean
datasource.autoproxy = false
}
}
registry.conf
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
#type = "file"
type = "nacos"
nacos {
serverAddr = "localhost:8848"
namespace = ""
cluster = "default"
}
eureka {
serviceUrl = "http://localhost:8761/eureka"
application = "default"
weight = "1"
}
redis {
serverAddr = "localhost:6379"
db = "0"
}
zk {
cluster = "default"
serverAddr = "127.0.0.1:2181"
session.timeout = 6000
connect.timeout = 2000
}
consul {
cluster = "default"
serverAddr = "127.0.0.1:8500"
}
etcd3 {
cluster = "default"
serverAddr = "http://localhost:2379"
}
sofa {
serverAddr = "127.0.0.1:9603"
application = "default"
region = "DEFAULT_ZONE"
datacenter = "DefaultDataCenter"
cluster = "default"
group = "SEATA_GROUP"
addressWaitTime = "3000"
}
file {
name = "file.conf"
}
}
config {
# file、nacos 、apollo、zk、consul、etcd3
type = "file"
nacos {
serverAddr = "localhost"
namespace = ""
}
consul {
serverAddr = "127.0.0.1:8500"
}
apollo {
app.id = "seata-server"
apollo.meta = "http://192.168.1.204:8801"
}
zk {
serverAddr = "127.0.0.1:2181"
session.timeout = 6000
connect.timeout = 2000
}
etcd3 {
serverAddr = "http://localhost:2379"
}
file {
name = "file.conf"
}
}
domain
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Order {
private Long id;
private Long userId;
private Long productId;
private BigDecimal money;
private Integer status;
}
@Data
@NoArgsConstructor
@AllArgsConstructor
public class CommonResult {
private Integer code;
private String message;
private T data;
public CommonResult(Integer code,String message){
this(code,message,null);
}
}
dao
@Mapper
public interface OrderDao {
void create(Order order);
void update(@Param("userId") Long userId,@Param("status")Integer status);
}
insert into t_order (id,user_id,product_id,`count`,money,status)
values (null,#{userId},#{productId},#{count},#{money},0);
update t_order set status=1 where user_id=#{userId} and status=#{status};
service
@Service
@Slf4j
public class OrderServiceImpl implements OrderService {
@Resource
private OrderDao orderDao;
@Resource
private StorageService storageService;
@Resource
private AccountService accountService;
@Override
public void create(Order order) {
log.info("---------->开始新建订单");
orderDao.create(order);
log.info("---------->订单微服务开始调用库存,做扣减count");
storageService.decrease(order.getProductId(),order.getCount());
log.info("---------->订单微服务开始调用库存,做扣减end");
log.info("---------->订单微服务开始调用账户,做扣减money");
accountService.decrease(order.getUserId(),order.getMoney());
log.info("---------->订单微服务开始调用账户,做扣减end");
log.info("---------->修改订单状态开始");
orderDao.update(order.getUserId(),0);
log.info("---------->修改订单状态结束");
log.info("---------->下订单结束了!");
}
}
controller
@RestController
@Slf4j
public class OrderController {
@Resource
public OrderService orderService;
@GetMapping("/order/create")
public CommonResult create(Order order){
orderService.create(order);
return new CommonResult(200,"订单创建成功");
}
}
config
@Configuration
public class DataSourceProxyConfig {
@Value("${mybatis.mapper-locations")
private String mapperLocations;
@Bean
@ConfigurationProperties(prefix = "spring.datasource")
public DataSource druidDataSource(){
return new DruidDataSource();
}
@Bean
public DataSourceProxy dataSourceProxy(DataSource dataSource){
return new DataSourceProxy(dataSource);
}
@Bean
public SqlSessionFactory sqlSessionFactoryBean(DataSourceProxy dataSourceProxy) throws Exception {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dataSourceProxy);
sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(mapperLocations));
sqlSessionFactoryBean.setTransactionFactory(new SpringManagedTransactionFactory());
return sqlSessionFactoryBean.getObject();
}
}
主启动
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
@EnableDiscoveryClient
@EnableFeignClients
public class OrderMain2001 {
public static void main(String[] args) {
SpringApplication.run(OrderMain2001.class,args);
}
}
创建seata-storage-service2002项目
pom.xml文件与2001一样
application.yml基本一样
file.conf和register.conf一样
domain
@AllArgsConstructor
@NoArgsConstructor
@Data
public class Storage {
private Long id;
private Long productId;
private Integer total;
private Integer used;
private Integer residue;
}
dao
@Mapper
public interface StorageDao {
void decrease(@Param("productId")Long productId,@Param("count")Integer count);
}
update t_storage
set used=used+#{count},residue=residue-#{count}
where product_id=#{productId};
service
public interface StorageService {
void decrease(Long productId, Integer count);
}
@Service
public class StorageServiceImpl implements StorageService {
private static final Logger LOGGER= LoggerFactory.getLogger(StorageServiceImpl.class);
@Resource
private StorageDao storageDao;
@Override
public void decrease(Long productId, Integer count) {
LOGGER.info("--------->storage-service中扣减库存开始");
storageDao.decrease(productId,count);
LOGGER.info("------------->storage-service中扣减库存结束");
}
}
config与2001一样
controller
@RestController
@Slf4j
public class StorageController {
@Autowired
private StorageService storageService;
@RequestMapping("/storage/decrease")
public CommonResult decrease(Long productId,Integer count){
storageService.decrease(productId,count);
return new CommonResult(200,"扣减库存成功!");
}
}
创建seata-account-service2003项目
pom.xml文件与2001一样
application.yml基本一样
file.conf和register.conf一样
domain
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Account {
private Long id;
private Long userId;
private BigDecimal total;
private BigDecimal usedT;
private BigDecimal residue;
}
dao
@Mapper
public interface AccountDao {
void decrease(@Param("userId")Long userId, @Param("money")BigDecimal money);
}
update t_account
set residue = residue-#{money},usedT = usedT + #{money}
where user_id=#{userId};
service
public interface AccountService {
void decrease(Long userId, BigDecimal money);
}
@Service
public class AccountServiceImpl implements AccountService {
private static final Logger LOGGER= LoggerFactory.getLogger(AccountServiceImpl.class);
@Resource
private AccountDao accountDao;
@Override
public void decrease(Long userId, BigDecimal money) {
LOGGER.info("--------->account-service中扣减库存开始");
accountDao.decrease(userId,money);
LOGGER.info("------------->account-service中扣减库存结束");
}
}
config与2001一样
controller
@RestController
@Slf4j
public class AccountController {
@Resource
AccountService accountService;
@RequestMapping("/account/decrease")
public CommonResult decrease(@RequestParam("userId")Long userId, @RequestParam("money")BigDecimal money){
accountService.decrease(userId,money);
return new CommonResult(200,"扣减账余额成功!");
}
}
正常下单:
超时异常:
@Service
public class AccountServiceImpl implements AccountService {
private static final Logger LOGGER= LoggerFactory.getLogger(AccountServiceImpl.class);
@Resource
private AccountDao accountDao;
@Override
public void decrease(Long userId, BigDecimal money) {
LOGGER.info("--------->account-service中扣减库存开始");
try{
TimeUnit.SECONDS.sleep(20000);
}catch (InterruptedException e){
e.printStackTrace();
}
accountDao.decrease(userId,money);
LOGGER.info("------------->account-service中扣减库存结束");
}
}
当库存和账户金额扣减后,订单状态并没有设置为已经完成,没有从零改为1而且由于feign的重试机制,账户余额还有可能被多次扣减。
@GlobalTransactional测试:
@Override
@GlobalTransactional(name = "fsp-create-order",rollbackFor = Exception.class)
public void create(Order order) {
log.info("---------->开始新建订单");
orderDao.create(order);
log.info("---------->订单微服务开始调用库存,做扣减count");
storageService.decrease(order.getProductId(),order.getCount());
log.info("---------->订单微服务开始调用库存,做扣减end");
log.info("---------->订单微服务开始调用账户,做扣减money");
accountService.decrease(order.getUserId(),order.getMoney());
log.info("---------->订单微服务开始调用账户,做扣减end");
log.info("---------->修改订单状态开始");
orderDao.update(order.getUserId(),0);
log.info("---------->修改订单状态结束");
log.info("---------->下订单结束了!");
}
下单后数据库教据并没有任何改变;记录都添加不进来少。
Seata:2019年1月份蚂蚁金服和阿里巴巴共同开源的分布式事务解决方案 Simple Extensible Autonomous Transaction Architecture,简单可扩展自治事务框架。
TM开启分布式事务(TM向TC注册全局事务记录); 按业务场景,编排数据库、服务等事务内资源(RM向TC汇报资源准备状态); TM结束分布式事务,事务一阶段结束(TM通知TC提交/回滚分布式事务); TC汇总事务信息,决定分布式事务是提交还是回滚; TC通知所有RM提交/回滚资源,事务二阶段结束。
在一阶段,Seata 会拦截“业务SQL”, 1.解析SQL语义,找到“业务SQL”要更新的业务数据,在业务数据被更新前,将其保存成“before image”, 2.执行“业务SQL”更新业务数据,在业务数据更新之后, 3.其保存成“after image”,最后生成行锁。 以上操作全部在一个数据库事务内完成,这样保证了一阶段操作的原子性。
二阶段如是顺利提交的话,因为“业务SQL”在一阶段已经提交至数据库,所以Seata框架只需将一阶段保存的快照数据和行锁删掉,完成数据清理即可。
二阶段回滚:二阶段如果是回滚的话,Seata就需要回滚一阶段已经执行的“业务SQL”,还原业务数据。回滚方式便是用“before image”还原业务数据;但在还原前要首先要校验脏写,对比“数据库当前业务数据”和“after image"如果两份数据完全一致就说明没有脏写,可以还原业务数据,如果不一致就说明有脏写,出现脏写就需要转人工处理。
总结:Seata的 AT、XA模式都是基于全局事务实现的,在高并发的场景下会出现获取全局锁异常,因此这两种模式都不适用高并发场景;Seata TCC模式性能比AT模式的好一点,但是并发量大于100的话还是不适合;如果基本没有什么并发量的话,可以选择AT模式;并发量在一百内的话可以使用TCC模式。